Author(s): Elena Carcano; Paolo Bartolini

Linked Author(s): Elena Carcano

Keywords: Recession curves; Flow duration curves; Mean flows; Low flows

Abstract: This paper presents a novel approach in assessing low flow sequences relying on two different perspectives. Increasing water requests can be granted as long as further uses of a river course are not totally compromised, and environmental features are also protected. The immediate effect of a water concession is a continuous drawing from the source and a reduction of mean annual superficial flow. Therefore, deciding if a water concession is appropriate seems to be easily solved by comparing the generic demand to the mean annual streamflow value at disposal. However, it must be noticed that streamflow data is an information available only for few catchments and, most often, limited to specific sites. Subsequently, comparing the generic water demand to mean daily discharge is indeed far from being completely satisfactory since the mean daily streamflow is greater than the water withdrawal for most of the year. In order to overcome the limit of an unbalanced comparison, the study aims to complete the information provided by classical flow duration curves (FDCs) introducing a link between such curves and recession curves thus showing the chronological sequence of flows with a particular focus on low flows. Results show groups of hydrologically homogeneous catchments, having the lower part of the FDCs smoothly reproduced by a common recession curve. The novelty of the paper consists in providing quite reliable answers to water requests, especially for those catchments which show similar hydrological response and can be used for a focused regionalization approach on low flows.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p1628-cd

Year: 2023